U.S. patent number 10,981,853 [Application Number 16/771,409] was granted by the patent office on 2021-04-20 for method for preparing .alpha.,.beta.-unsaturated aldehyde.
This patent grant is currently assigned to Kao Corporation. The grantee listed for this patent is Kao Corporation. Invention is credited to Tsubasa Arai, Kensuke Karasu, Kensuke Masumura, Yuki Nakagawa.
![](/patent/grant/10981853/US10981853-20210420-C00001.png)
![](/patent/grant/10981853/US10981853-20210420-C00002.png)
![](/patent/grant/10981853/US10981853-20210420-C00003.png)
![](/patent/grant/10981853/US10981853-20210420-C00004.png)
![](/patent/grant/10981853/US10981853-20210420-C00005.png)
![](/patent/grant/10981853/US10981853-20210420-C00006.png)
![](/patent/grant/10981853/US10981853-20210420-C00007.png)
![](/patent/grant/10981853/US10981853-20210420-C00008.png)
![](/patent/grant/10981853/US10981853-20210420-C00009.png)
![](/patent/grant/10981853/US10981853-20210420-C00010.png)
United States Patent |
10,981,853 |
Arai , et al. |
April 20, 2021 |
Method for preparing .alpha.,.beta.-unsaturated aldehyde
Abstract
The present invention aims to provide a method for preparing an
aldehyde, which can prepare a target aldehyde with high selectivity
and can also suppress the production of by-products. The present
invention relates to a method for preparing an
.alpha.,.beta.-unsaturated aldehyde. The method includes a step of
reacting a compound of formula (I) with a compound of formula (II)
to provide an .alpha.,.beta.-unsaturated aldehyde of formula (III).
An alkali metal hydroxide and an alkanol having 1 to 4 carbon atoms
are used in the step. The amount of the alkali metal hydroxide is 8
mol % or more and 12 mol % or less with respect to the compound of
formula (I). The total amount of water contained in materials that
are used in the reaction is 10 mol % or more and 50 mol % or less
with respect to the compound of formula (I). ##STR00001##
Inventors: |
Arai; Tsubasa (Wakayama,
JP), Masumura; Kensuke (Wakayama, JP),
Karasu; Kensuke (Wakayama, JP), Nakagawa; Yuki
(Wakayama, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Kao Corporation |
Tokyo |
N/A |
JP |
|
|
Assignee: |
Kao Corporation (Tokyo,
JP)
|
Family
ID: |
1000005498850 |
Appl.
No.: |
16/771,409 |
Filed: |
June 12, 2018 |
PCT
Filed: |
June 12, 2018 |
PCT No.: |
PCT/JP2018/022404 |
371(c)(1),(2),(4) Date: |
June 10, 2020 |
PCT
Pub. No.: |
WO2019/116608 |
PCT
Pub. Date: |
June 20, 2019 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200347003 A1 |
Nov 5, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
Dec 12, 2017 [JP] |
|
|
JP2017-237934 |
May 31, 2018 [JP] |
|
|
JP2018-104435 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C
45/74 (20130101) |
Current International
Class: |
C07C
45/72 (20060101); C07C 45/74 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
101265167 |
|
Sep 2008 |
|
CN |
|
102719638 |
|
Oct 2012 |
|
CN |
|
103539647 |
|
Jan 2014 |
|
CN |
|
3-14535 |
|
Jan 1991 |
|
JP |
|
4-112846 |
|
Apr 1992 |
|
JP |
|
5-168928 |
|
Jul 1993 |
|
JP |
|
2003-511431 |
|
Mar 2003 |
|
JP |
|
2005-342675 |
|
Dec 2005 |
|
JP |
|
2007-513919 |
|
May 2007 |
|
JP |
|
2007-153818 |
|
Jun 2007 |
|
JP |
|
4806354 |
|
Nov 2011 |
|
JP |
|
4886283 |
|
Feb 2012 |
|
JP |
|
2012-126676 |
|
Jul 2012 |
|
JP |
|
5001549 |
|
Aug 2012 |
|
JP |
|
5143438 |
|
Feb 2013 |
|
JP |
|
2014-9167 |
|
Jan 2014 |
|
JP |
|
2014-118394 |
|
Jun 2014 |
|
JP |
|
2014-139158 |
|
Jul 2014 |
|
JP |
|
2015-143220 |
|
Aug 2015 |
|
JP |
|
Other References
International Search Report dated Aug. 21, 2018 in
PCT/JP2018/022404 filed on Jun. 12, 2018, 2 pages. cited by
applicant .
Vashishtha, M. et al., "A novel approach for selective cross aldol
condensation using reusable NaOH-cationic micellar systems,"
Applied Catalysis A: General, vol. 466, 2013, pp. 38-44. cited by
applicant .
Office Action in corresponding Indian Patent Application No.
202017027768 dated Nov. 13, 2020. cited by applicant .
N. Sudheesh, et al., "Chitosan as an eco-friendly solid base
catalyst for the solvent-free synthesis of jasminaldehyde", Journal
of Molecular Catalysis A: Chemical, vol. 321, 2010, pp. 77-82.
cited by applicant.
|
Primary Examiner: Witherspoon; Sikarl A
Attorney, Agent or Firm: Oblon, McClelland, Maier &
Neustadt, L.L.P.
Claims
The invention claimed is:
1. A method for preparing an .alpha.,.beta.-unsaturated aldehyde,
comprising: reacting a compound of formula (I) with a compound of
formula (II) to provide an .alpha.,.beta.-unsaturated aldehyde of
formula (III) in the presence of an alkali metal hydroxide and an
alkanol having 1 to 4 carbon atoms, wherein an amount of the alkali
metal hydroxide is 8 mol % or more and 12 mol % or less with
respect to an amount of the compound of formula (I), and a total
amount of water contained in materials that are used in the
reaction is 10 mol % or more and 50 mol % or less with respect to
the amount of the compound of formula (I), ##STR00009## where
R.sup.1 represents a hydrogen atom or an alkyl group having 1 to 10
carbon atoms, R.sup.2 represents a hydrogen atom, an alkyl group
having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon
atoms, R.sup.3 represents a hydrogen atom, or R.sup.2 and R.sup.3
form 1,3-dioxolane together with carbon atoms to which R.sup.2 and
R.sup.3 are bound, and R.sup.4, R.sup.5, and R.sup.6 each
independently represent a hydrogen atom or an alkyl group having 1
to 3 carbon atoms.
2. The method for preparing the .alpha.,.beta.-unsaturated aldehyde
according to claim 1, wherein an amount of the compound of formula
(II) used in the reaction is 1.5 equivalents or more with respect
to the amount of the compound of formula (I).
3. The method for preparing the .alpha.,.beta.-unsaturated aldehyde
according to claim 1, wherein the total amount of water contained
in the materials that are used in the reaction is 12.5 mol % or
more and 30 mol % or less with respect to the amount of the
compound of formula (I).
4. The method for preparing the .alpha.,.beta.-unsaturated aldehyde
according to claim 1, wherein R.sup.1 represents an alkyl group
having 3 to 8 carbon atoms.
5. The method for preparing the .alpha.,.beta.-unsaturated aldehyde
according to claim 1, wherein the compound of formula (II) is a
compound represented by any one of the following formulas:
##STR00010##
6. The method for preparing the .alpha.,.beta.-unsaturated aldehyde
according to claim 1, wherein the alkali metal hydroxide is lithium
hydroxide, sodium hydroxide, or potassium hydroxide.
7. The method for preparing the .alpha.,.beta.-unsaturated aldehyde
according to claim 1, wherein the alkanol having 1 to 4 carbon
atoms is methanol or ethanol.
8. The method for preparing the .alpha.,.beta.-unsaturated aldehyde
according to claim 1, wherein an amount of the alkanol having 1 to
4 carbon atoms is 300 mol % to 500 mol % with respect to the amount
of the compound of formula (I).
9. The method for preparing the .alpha.,.beta.-unsaturated aldehyde
according to claim 1, wherein the reaction includes adding the
compound of formula (I) dropwise to a mixture of the alkanol, the
alkali metal hydroxide, and the compound of formula (II).
10. The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to claim 9, wherein the compound of formula (I)
is added dropwise for a drop time of 3 hours or more and 9 hours or
less.
11. The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to claim 9, wherein the compound of formula (I)
is added dropwise by changing a drop rate in multiple stages.
12. The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to claim 9, wherein the compound of formula (I)
is added dropwise by changing a drop rate in two stages.
13. The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to claim 12, wherein the two stages include a
stage corresponding to a first half period of a drop time and a
stage corresponding to a second half period of the drop time, and
the drop rate during the second half period of the drop time is 0.2
times or more and 0.9 times or less the drop rate during the first
half period of the drop time.
Description
TECHNICAL FIELD
The present invention relates to a method for preparing an
.alpha.,.beta.-unsaturated aldehyde.
BACKGROUND ART
An aldehyde is a useful compound as, e.g., a material for a
chemical reaction, or an intermediate for perfume, medicine, or
agricultural chemicals. In particular, an
.alpha.,.beta.-unsaturated aldehyde having a specific molecular
weight is useful in itself as a fragrance material, and further is
also used as a raw material for derivatives with different
fragrance notes.
As a method for preparing an aldehyde, e.g., dehydrogenation or
oxidation using alcohol as a raw material has conventionally been
known. In particular, a cross-aldol condensation reaction between
two types of aldehydes is frequently used as a method for preparing
an .alpha.,.beta.-unsaturated aldehyde. Moreover, various studies
have been made on the reaction conditions of the cross-aldol
condensation reaction.
For example, Patent Document 1 discloses the continuous production
of cinnamaldehyde and dihydrocinnamaldehyde. In this method,
benzaldehyde derivatives are continuously reacted with alkanals in
a plant that includes a plurality of reactors in a cascade
system.
Patent Document 2 discloses a method for preparing an
.alpha.-substituted cinnamaldehyde. This method is performed in a
solvent containing glycol.
On the other hand, Patent Document 3 discloses a method for
preparing 2,3-cis-substituted 2-arylpropenals by condensing a
2-arylacetaldehyde with a nonenolizable aldehyde. In this method, a
solvent contains a specific amount of moisture.
PRIOR ART DOCUMENTS
Patent Documents
Patent Document 1: JP 2003-511431 A
Patent Document 2: JP H3(1991)-14535 A
Patent Document 3: JP 2007-513919 A
DISCLOSURE OF INVENTION
Problem to be Solved by the Invention
The cross-aldol condensation reaction is known to cause side
reactions such as dimerization (self-aldol condensation reaction)
and disproportionation (Cannizzaro reaction) between the same type
of aldehydes. If the side reactions proceed, it is difficult to
isolate the target aldehyde, and the yield is reduced.
With the foregoing in mind, the present invention provides a method
for preparing an .alpha.,.beta.-unsaturated aldehyde, which can
prepare a target aldehyde with high selectivity and can also
suppress the production of by-products.
Means for Solving Problem
The present inventors found that it was possible to obtain the
target aldehyde with high selectivity and to suppress the
production of by-products in the cross-aldol condensation reaction
by adjusting the total amount of water contained in the materials
that were used in the reaction to a specific amount.
The present invention provides a method for preparing an
.alpha.,.beta.-unsaturated aldehyde, including a step of reacting a
compound of formula (I) with a compound of formula (II) to provide
an .alpha.,.beta.-unsaturated aldehyde of formula (III),
wherein an alkali metal hydroxide and an alkanol having 1 to 4
carbon atoms are used in the step,
an amount of the alkali metal hydroxide is 8 mol % or more and 12
mol % or less with respect to the compound of formula (I), and a
total amount of water contained in materials that are used in the
reaction is 10 mol % or more and 50 mil % or less with respect to
the compound of formula (I),
[Chemical Formula 1]
##STR00002##
In the above formula, R.sup.1 represents a hydrogen atom or an
alkyl group having 1 to 10 carbon atoms,
R.sup.2 represents a hydrogen atom, an alkyl group having 1 to 6
carbon atoms, or an alkoxy group having 1 to 6 carbon atoms,
R.sup.3 represents a hydrogen atom, or
R.sup.2 and R.sup.3 form 1,3-dioxolane together with carbon atoms
to which R.sup.2 and R.sup.3 are bound, and
R.sup.4, R.sup.5, and R.sup.6 each independently represent a
hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
Effects of the Invention
The present invention can provide a method for preparing an
.alpha.,.beta.-unsaturated aldehyde, which can prepare a target
aldehyde with high selectivity and can also suppress the production
of by-products.
DESCRIPTION OF THE INVENTION
In the method for preparing an .alpha.,.beta.-unsaturated aldehyde
of the present invention, the cross-aldol condensation reaction
between the compound of formula (I) and the compound of formula
(II) involves the use of a specific amount of water in addition to
the alkali metal hydroxide and the alkanol that serve as
catalysts.
[Compound of Formula (I)]
In the compound of formula (I), R.sup.1 represents a hydrogen atom
or an alkyl group having 1 to 10 carbon atoms. R.sup.1 is
preferably an alkyl group having 1 to 10 carbon atoms. From the
viewpoint of the reactivity of the cross-aldol condensation
reaction and the usefulness of the aldehyde to be prepared as a
fragrance material, the alkyl group having 1 to 10 carbon atoms is
preferably an alkyl group having 2 or more carbon atoms, and more
preferably an alkyl group having 3 or more carbon atoms.
Furthermore, the alkyl group having 1 to 10 carbon atoms is
preferably an alkyl group having 8 or less carbon atoms, and more
preferably an alkyl group having 7 or less carbon atoms. The alkyl
group having 1 to 10 carbon atoms may be either a straight-chain
alkyl group or a branched-chain alkyl group, and is preferably a
straight-chain alkyl group. Examples of the alkyl group having 1 to
10 carbon atoms include methyl, ethyl, n-propyl, isopropyl,
2-methylpropyl, n-butyl, t-butyl, pentyl, hexyl, heptyl, octyl,
nonyl, and decyl. Examples of the compound of formula (I) include
acetaldehyde, propionaldehyde, butanal, pentanal, hexanal, octanal,
nonanal, decanal, and dodecanal. From the viewpoint of the
reactivity of the cross-aldol condensation reaction, the compound
of formula (I) is preferably propionaldehyde, butanal, pentanal,
hexanal, octanal, nonanal, or decanal, more preferably pentanal,
hexanal, octanal, nonanal, or decanal, and even more preferably
pentanal, hexanal, octanal, or nonanal.
[Compound of Formula (II)]
In the compound of formula (II), R.sup.2 represents a hydrogen
atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group
having 1 to 6 carbon atoms. R.sup.2 is preferably a hydrogen atom
or an alkyl group having 1 to 6 carbon atoms, and more preferably a
hydrogen atom-group. From the viewpoint of the reactivity of the
cross-aldol condensation reaction and the usefulness of the
aldehyde to be prepared as a fragrance material, the alkyl group
having 1 to 6 carbon atoms is preferably an alkyl group having 1 or
more carbon atoms. Furthermore, the alkyl group having 1 to 6
carbon atoms is preferably an alkyl group having 5 or less carbon
atoms, and more preferably an alkyl group having 4 or less carbon
atoms. Examples of the alkyl group having 1 to 6 carbon atoms
include methyl, ethyl, n-propyl, isopropyl, 2-methylpropyl,
n-butyl, t-butyl, pentyl, and hexyl. The alkoxy group having 1 to 6
carbon atoms is an alkyloxy group having 1 to 6 carbon atoms.
Examples of the alkoxy group having 1 to 6 carbon atoms include
methoxy, ethoxy, n-propyloxy, isopropyloxy, 2-methylpropyloxy,
n-butyloxy, t-butyloxy, pentyloxy, and hexyloxy. From the viewpoint
of the reactivity of the cross-aldol condensation reaction and the
usefulness of the aldehyde to be prepared as a fragrance material,
the alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy
group having 1 to 5 carbon atoms, and more preferably an alkoxy
group having 1 to 4 carbon atoms.
In the composition of formula (II), when R.sup.2 and R.sup.3 form
1,3-dioxolane together with carbon atoms to which R.sup.2 and
R.sup.3 are bound, the compound of formula (II) is represented by
the following formula,
##STR00003##
In the above formula, R.sup.4, R.sup.5, and R.sup.6 are as defined
in the formula (II).
In the compound of formula (II), R.sup.4, R.sup.5, and R.sup.6 each
independently represent a hydrogen atom or an alkyl group having 1
to 3 carbon atoms. R.sup.4, R.sup.5, and R.sup.6 are preferably
hydrogen atoms. From the viewpoint of the usefulness of the
aldehyde to be prepared as a fragrance material, the alkyl group
having 1 to 3 carbon atoms is preferably an alkyl group having 1 to
2 carbon atoms, and more preferably an alkyl group having 1 carbon
atom. Examples of the alkyl group having 1 to 3 carbon atoms
include methyl, ethyl, n-propyl, and isopropyl.
The compound of formula (II) is preferably, e.g., any of the
following compounds.
##STR00004##
In the present invention, the amount of the compound of formula
(II) used is preferably 1 equivalent or more, and more preferably
1.5 equivalents or more with respect to the compound of formula
(I). Furthermore, the amount of the compound of formula (II) used
is preferably 5 equivalents or less, and more preferably 3
equivalents or less with respect to the compound of formula (I)
[Alkali Metal Hydroxide]
In the present invention, the alkali metal hydroxide may be, e.g.,
lithium hydroxide, sodium hydroxide, or potassium hydroxide. From
the viewpoint of reaction efficiency, the alkali metal hydroxide is
preferably sodium hydroxide or potassium hydroxide, and more
preferably potassium hydroxide.
In the present invention, the amount of the alkali metal hydroxide
is 8 mol % or more and 12 mol % or less with respect to the
compound of formula (I). From the viewpoint of reaction efficiency,
the amount of the alkali metal hydroxide is preferably 9 mol % or
more and preferably 11 mol % or less with respect to the compound
of formula (I). This is because the disproportionation of the
compound of formula (II) can be suppressed by reducing the amount
of the alkali metal hydroxide, and thus the production of
by-products can be suppressed.
[Alkanol Having 1 to 4 Carbon Atoms]
In the present invention, the alkanol having 1 to 4 carbon atoms is
an alkyl alcohol having 1 to 4 carbon atoms. Examples of the
alkanol having 1 to 4 carbon atoms include methanol, ethanol,
n-propanol, isopropanol, n-butanol, t-butanol, ethylene glycol,
propylene glycol, and diethylene glycol. From the viewpoint of
reaction efficiency, the alkanol having 1 to 4 carbon atoms is
preferably an alkanol having 1 to 3 carbon atoms, and more
preferably an alkanol having 1 to 2 carbon atoms. Furthermore, from
the viewpoint of reaction efficiency, the alkanol having 1 to 4
carbon atoms is preferably ethanol or methanol, and more preferably
methanol.
In the present invention, from the viewpoint of achieving high
reaction efficiency while suppressing a side reaction, the amount
of the alkanol having 1 to 4 carbon atoms is preferably 300 mol %
or more, and more preferably 350 mol % or more with respect to the
compound of formula (I). Furthermore, the amount of the alkanol
having 1 to 4 carbon atoms is preferably 500 mol % or less, and
more preferably 450 mol % or less with respect to the compound of
formula (I). The amount of the alkanol having 1 to 4 carbon atoms
is preferably 300 mol % to 500 mol %.COPYRGT., and more preferably
350 mol % to 450 mol % with respect to the compound of formula
(I).
[Total Amount of Water Contained in Materials Used in Reaction]
In the present invention, the total amount of water contained in
the materials that are used in the reaction means the total amount
of water contained in the alkali metal hydroxide, the alkanol, the
compound of formula (I), the compound of formula (II), and other
materials used in the reaction. When water is added during the
reaction, the total amount of water contained in the materials that
are used in the reaction means the sum of the amount of the water
added and the amount of water contained in the alkali metal
hydroxide, the alkanol, the compound of formula (I), the compound
of formula (II), and compounds of other materials used in the
reaction.
In the present invention, in the step of reacting the compound of
formula (I) with the compound of formula (II) to provide the
.alpha.,.beta.-unsaturated aldehyde of formula from the viewpoint
of achieving high reaction efficiency while suppressing a side
reaction, the total amount of water contained in the materials that
are used in the reaction is 10 mol % or more, preferably 12.5 mol %
or more, and more preferably 14 mol % or more with respect to the
compound of formula (I). Furthermore, from the viewpoint of
achieving high reaction efficiency while suppressing a side
reaction, the amount of moisture is 50 mol % or less, preferably 30
mol % or less, and more preferably 25 mol % or less with respect to
the compound of formula (I). The amount of moisture also includes
moisture contained in the alkali metal hydroxide, the alkanol, the
compound of formula (I), and the compound of formula (II). If the
amount of moisture is outside the above specific range, the total
amount of water contained in the compound of formula (II) and the
compounds of other materials used in the reaction may be adjusted
to 10 mol % or more and 50 mol % or less with respect to the
compound of formula (I). The adjustment process may be performed by
adding water to the materials used in the reaction. Alternatively,
the adjustment process may be performed by using a material that
previously contains water.
The amount of moisture in the system can be determined in the
following manner. Each of the materials is measured by a Karl
Fischer volumetric titration method, and then the amounts of
moisture thus obtained are added together. Alternatively, the
amount of moisture in the system can be determined by measuring a
mixture of the materials.
In the present invention, the effect of containing a predetermined
amount of moisture in the materials used in the reaction can be
considered as follows. Due to the presence of a predetermined
amount of moisture in the materials used in the reaction, the
reaction solution changes from a homogeneous phase system to an
oil-water two-phase system in the middle of the reaction, so that
the reaction rate is relaxed. When the amount of moisture is 10 mol
% or more with respect to the compound of formula (I), the reaction
activity is appropriate, and thus the disproportionation of the
compound of formula (II) can be suppressed. Accordingly, this range
is deemed to be preferable. On the other hand, when the amount of
moisture is 50 mol % or less with respect to the compound of
formula (I), the reaction to provide the .alpha.,.beta.-unsaturated
aldehyde of formula (III) proceeds sufficiently before the reaction
rate is relaxed, and thus the dimerization of the compound of
formula (I) can be suppressed. Accordingly, this range is deemed to
be preferable. In other words, the amount of moisture that falls in
the range of 10 mol % to 50 mol % with respect to the compound of
formula (I) may be advantageous for the following reasons. Since
the reaction to provide the .alpha.,.beta.-unsaturated aldehyde of
formula (III) proceeds rapidly, the dimerization of the compound of
formula (I) is suppressed. Then, the reaction solution changes to
the oil-water two-phase system, which relaxes the reaction rate.
Therefore, while the disproportionation of the compound of formula
(II) is suppressed, the reaction to provide the
.alpha.,.beta.-unsaturated aldehyde of formula (III) is completed.
Consequently, the .alpha.,.beta.-unsaturated aldehyde of formula
(III) can be prepared with a high yield.
[Reaction Step]
In the present invention, from the viewpoint of reaction
efficiency, the step of reacting the compound of formula (I) with
the compound of formula (II) to provide the
.alpha.,.beta.-unsaturated aldehyde of formula (III) is performed
preferably at 20.degree. C. or more, and more preferably at
25.degree. C. or more. Furthermore, this step is performed
preferably at 50.degree. C. or less, and more preferably at
40.degree. C. or less.
In the present invention, from the viewpoint of reaction
efficiency, the step of reacting the compound of formula (I) with
the compound of formula (II) to provide the
.alpha.,.beta.-unsaturated aldehyde of formula (III) may be
performed in an atmosphere of inert gas. From the viewpoint of
reaction efficiency, the inert gas is preferably nitrogen or noble
gas (elements in Group 18), and more preferably nitrogen. The noble
gas may be, e.g., argon or helium and is preferably argon.
In the present invention, the step of reacting the compound of
formula (I) with the compound of formula (II) to provide the
.alpha.,.beta.-unsaturated aldehyde of formula (III) may be
performed in the following manner. First, a solution in which the
alkali metal hydroxide is dissolved in the alkanol is placed in a
reaction vessel. Then, the compound of formula (II) is placed in
the reaction vessel. Subsequently, the compound of formula (I) is
added dropwise to the mixture thus obtained. In such a case, e.g.,
the compound of formula (I) may be added dropwise to a mixture of
the alkanol, the alkali metal hydroxide, and the compound of
formula (II). This is because the concentration of the compound of
formula (I) in the reaction system is kept low by the dropwise
addition of the compound of formula (I) to the reaction system, so
that the dimerization of the compound of formula (I) can be
suppressed. At the start of chopping, the total amount of water
contained in the materials that are used in the reaction is
adjusted to 10 mol % or more and 50 mol % or less with respect to
the compound of formula (I). Specifically, the compound of formula
(I) may be dropped for 3 hours or more and 9 hours or less, and
preferably for 5 hours or more and 7 hours or less from the
viewpoint of reaction efficiency.
When the compound of formula (I) is added dropwise to the mixture
of the alkanol, the alkali metal hydroxide, and the compound of
formula (II), the drop rate may be changed in multiple stages. The
multiple stages may be two stages. From the viewpoint of reaction
efficiency, a relatively large amount of the compound of formula
(I) may be added for a predetermined period of time, and then a
relatively small amount of the compound of formula (I) may be added
for a predetermined period of time. Specifically, the compound of
formula (I) may be added dropwise by changing the chop rate in
multiple stages. More specifically, 55% by mass or more and 85% by
mass or less of the whole amount of addition of the compound of
formula (I) may be added during one half (i.e., the first half
period) of the drop time, and 15% by mass or more and 45% by mass
or less of the whole amount of addition of the compound of formula
(I) may be added during the other half (i.e., the second half
period) of the drop time. Moreover, the drop rate during one half
(i.e., the first half period) of the drop time may remain constant,
while the drop rate during the other half (i.e., the second half
period) of the drop time may be different from that in the first
half period and may remain constant. When the drop rate is changed
in two stages in the drop time, the drop rate during the other half
(i.e., the second half period) of the drop time is preferably 0.2
times or more, more preferably 0.3 times or more, and further
preferably 0.4 times or more the chop rate during one half the
first half period) of the drop time. Furthermore, the drop rate
during the other half (i.e., the second half period) of the drop
time is preferably 0.9 times or less, more preferably 0.8 times or
less, and further preferably 0.7 times or less the drop rate during
one half (i.e., the first half period) of the drop time.
In the present invention, when the step of reacting the compound of
formula (I) with the compound of formula (II) to provide the
.alpha.,.beta.-unsaturated aldehyde of formula (III) is performed
by placing a solution in which the alkali metal hydroxide is
dissolved in the alkanol in a reaction vessel, then placing the
compound of formula (II) in the reaction vessel, and adding the
compound of formula (I) dropwise to the mixture thus obtained, the
discharge portion of the compound of formula (I) may be located
above the reaction solution or inside the reaction solution.
In the present invention, when the step of reacting the compound of
formula (I) with the compound of formula (II) to provide the
.alpha.,.beta.-unsaturated aldehyde of formula (III) is performed
by placing a solution in which the alkali metal hydroxide is
dissolved in the alkanol in a reaction vessel, then placing the
compound of formula (II) in the reaction vessel, and adding the
compound of formula (I) dropwise to the mixture thus obtained,
stirring may be continued for a certain time after the completion
of the addition of the compound of formula (I) in order to
terminate the reaction between the compound of formula (I) and the
compound of formula (II). Specifically, the stirring may be
performed preferably for 10 minutes or more, and more preferably
for 20 minutes or more. Furthermore, the stirring may be performed
preferably for 60 minutes or less, and more preferably for 45
minutes or less.
In the present invention, after performing the step of reacting the
compound of formula (I) with the compound of formula (II) to
provide the .alpha.,.beta.-unsaturated aldehyde of formula (III),
an acid compound may be added to the reaction vessel so that the
alkali metal hydroxide is neutralized to stop the reaction, thereby
avoiding the production of by-products. The acid compound may be,
e.g., sulfuric acid, nitric acid, phosphoric acid, formic acid,
acetic acid, propionic acid, or a solution thereof,
Concerning the above embodiments, the present invention further
discloses a method for preparing an .alpha.,.beta.-unsaturated
aldehyde as follows.
<1> A method for preparing an .alpha.,.beta.-unsaturated
aldehyde, comprising a step of reacting a compound of formula (I)
with a compound of formula (H) to provide an
.alpha.,.beta.-unsaturated aldehyde of formula (III),
wherein an alkali metal hydroxide and an alkanol having 1 to 4
carbon atoms are used in the step,
an amount of the alkali metal hydroxide is 8 mol % or more and 12
mol % or less with respect to the compound of formula (I), and
a total amount of water contained in materials that are used in the
reaction (i.e., the total amount of water contained in the alkali
metal hydroxide, the alkanol, the compound of formula (I), the
compound of formula (II), and other materials used in the reaction;
when water is added during the reaction, it means the sum of the
amount of the water added and the amount of water contained in the
alkali metal hydroxide, the alkanol, the compound of formula (I),
the compound of formula (II), and compounds of other materials used
in the reaction) is 10 mol % or more and 50 mol % or less with
respect to the compound of formula (I).
##STR00005##
In the above formula, R.sup.1 represents a hydrogen atom or an
alkyl group having 1 to 10 carbon atoms,
R.sup.2 represents a hydrogen atom, an alkyl group having 1 to 6
carbon atoms, or an alkoxy group having 1 to 6 carbon atoms,
R.sup.3 represents a hydrogen atom, or
R.sup.2 and R.sup.3 form 1,3-dioxolane together with carbon atoms
to which R.sup.2 and R.sup.3 are bound, and
R.sup.4, R.sup.5, and R.sup.6 each independently represent a
hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
<2> A method for preparing an .alpha.,.beta.-unsaturated
aldehyde, comprising a step of reacting a compound of formula (I)
with a compound of formula (II) to provide an
.alpha.,.beta.-unsaturated aldehyde of formula (III),
wherein an alkali metal hydroxide and an alkanol having 1 to 4
carbon atoms are used in the step,
an amount of the alkali metal hydroxide is 8 mol % or more and 12
mol % or less with respect to the compound of formula (I), and
the step is performed so that a total amount of water contained in
materials that are used in the reaction (i.e., the total amount of
water contained in the alkali metal hydroxide, the alkanol, the
compound of formula (I), the compound of formula (II), and other
materials used in the reaction; when water is added during the
reaction, it means the sum of the amount of the water added and the
amount of water contained in the alkali metal hydroxide, the
alkanol, the compound of formula (I), the compound of formula (II),
and compounds of other materials used in the reaction) is adjusted
to 10 mol % or more and 50 mol % or less with respect to the
compound of formula (I).
##STR00006##
In the above formula, R.sup.1 represents a hydrogen atom or an
alkyl group having 1 to 10 carbon atoms,
R.sup.2 represents a hydrogen atom, an alkyl group having 1 to 6
carbon atoms, or an alkoxy group having 1 to 6 carbon atoms,
R.sup.3 represents a hydrogen atom, or
R.sup.2 and R.sup.3 form 1,3-dioxolane together with carbon atoms
to which R.sup.2 and R.sup.3 are bound, and
R.sup.4, R.sup.5, and R.sup.6 each independently represent a
hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
<3> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to <1> or <2>, wherein an amount of
the compound of formula (II) used in the step is preferably 1
equivalent or more, and more preferably 1.5 equivalents or more
with respect to the compound of formula (I) and is also preferably
5 equivalents or less, and more preferably 3 equivalents or less
with respect to the compound of formula (I).
<4> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <3>, wherein
the total amount of water contained in the materials that are used
in the reaction is preferably 12.5 mol % or more, and more
preferably 14 mol % or more with respect to the compound of formula
(I) and is also preferably 30 mol % or less, and more preferably 25
mol % or less with respect to the compound of formula (I).
<5> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <4>, wherein
the total amount of water contained in the materials that are used
in the reaction is 12.5 mol % or more and 30 mol % or less with
respect to the compound of formula (I).
<6> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <5>, wherein
the total amount of water contained in the materials that are used
in the reaction is 14 mol % or more and 25 mol % or less with
respect to the compound of formula (I).
<7> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <6>, wherein
R.sup.1 is preferably an alkyl group having 1 to 10 carbon atoms,
and the alkyl group having 1 to 10 carbon atoms is preferably an
alkyl group having 2 to 8 carbon atoms, more preferably an alkyl
group having 3 to 8 carbon atoms, and further preferably an alkyl
group having 3 to 7 carbon atoms.
<8> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <7>, wherein
the compound of formula (I) is acetaldehyde, propionaldehyde,
butanal, pentanal, hexanal, heptanal, octanal, nonanal, decanal, or
dodecanal, preferably propionaldehyde, butanal, pentanal, hexanal,
heptanal, octanal, nonanal, or decanal, more preferably pentanal,
hexanal, heptanal, octanal, nonanal, or decanal, and even more
preferably pentanal, hexanal, heptanal, octanal, or nonanal.
<9> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <8>, wherein
R.sup.2 is preferably a hydrogen atom or an alkyl group having 1 to
6 carbon atoms, and more preferably a hydrogen atom group.
<10> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <9>, wherein
the alkyl group represented by R.sup.2 is preferably an alkyl group
having 1 to 5 carbon atoms, and more preferably an alkyl group
having 1 to 4 carbon atoms.
<11> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <10>, wherein
the alkoxy group represented by R.sup.2 is preferably an alkoxy
group having 1 to 5 carbon atoms, and more preferably an alkoxy
group having 1 to 4 carbon atoms,
<12> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <11>, wherein
R.sup.3, R.sup.4, and R.sup.5 are preferably hydrogen atoms.
<13> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <12>, wherein
the compound of formula (II) is a compound represented by any one
of the following formulas.
##STR00007##
<14> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <12>, wherein
R.sup.1 represents an alkyl group having 2 to 8 carbon atoms,
R.sup.2 represents hydrogen or an alkyl group having 1 to 5 carbon
atoms, and R.sup.3 to R.sup.6 represent hydrogen.
<15> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <12> and
<14>, wherein R.sup.1 represents an alkyl group having 2 to 8
carbon atoms, R.sup.2 represents hydrogen or an alkyl group having
1 to 3 carbon atoms, and R.sup.3 to R.sup.6 represent hydrogen.
<16> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <12>, wherein
R.sup.1 represents an alkyl group having 2 to 8 carbon atoms, and
R.sup.2 to R.sup.6 represent hydrogen.
<17> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <16>, wherein
the step includes adding the compound of formula (I) dropwise to a
mixture of the alkanol, the alkali metal hydroxide, and the
compound of formula (II).
<18> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <17>, wherein
the alkali metal hydroxide is preferably lithium hydroxide, sodium
hydroxide, or potassium hydroxide, more preferably sodium hydroxide
or potassium hydroxide, and further preferably potassium
hydroxide.
<19> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <18>, wherein
an amount of the alkali metal hydroxide is preferably 9 mol % or
more and preferably 11 mol % or less with respect to the compound
of formula (I).
<20> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <19>, wherein
the amount of the alkali metal hydroxide is 8.5 mol % or more and
11.5 mol % or less with respect to the compound of formula W, and
the total amount of water is 14 mol % or more and 30 mol % or less
with respect to the compound of formula (I).
<21> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <19>, wherein
the amount of the alkali metal hydroxide is 8.5 mol % or more and
11.5 mol % or less with respect to the compound of formula W,
and
the total amount of water is 12.5 mol % or more and 30 mol % or
less with respect to the compound of formula (I).
<22> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <19>, wherein
the amount of the alkali metal hydroxide is 8.5 mol % or more and
11.5 mol % or less with respect to the compound of formula a
and
the total amount of water is 14 mol % or more and 25 mol % or less
with respect to the compound of formula (I).
<23> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <22>, wherein
the alkanol is preferably an alkanol having 1 to 3 carbon atoms,
and more preferably an alkanol having 1 to 2 carbon atoms.
<24> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <23>, wherein
an amount of the alkanol having 1 to 4 carbon atoms is preferably
300 mol % to 500 mol %, and more preferably 350 mol % to 450 mol %
with respect to the compound of formula (I).
<25> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <24>, wherein
the step of reacting the compound of formula (I) with the compound
of formula (II) to provide the .alpha.,.beta.-unsaturated aldehyde
of formula (III) is performed preferably at 20.degree. C. or more,
and more preferably at 25.degree. C. or more and also performed
preferably at 50.degree. C. or less, and more preferably at
40.degree. C. or less.
<26> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <25>, wherein
the step of reacting the compound of formula (I) with the compound
of formula (II) to provide the .alpha.,.beta.-unsaturated aldehyde
of formula (III) is performed in an atmosphere of inert gas
(preferably nitrogen or noble gas (elements in Group 18, including,
e.g., argon and helium, and preferably argon), and more preferably
nitrogen),
<27> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <17> to <26>, wherein
the compound of formula (I) is added dropwise for a drop time of
preferably 3 hours or more and 9 hours or less, and more preferably
5 hours or more and 7 hours or less.
<28> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <17> to <27>, wherein
the compound of formula (I) is added dropwise by changing a drop
rate in multiple stages.
<29> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <17> to <28>, wherein
the compound of formula (I) is added dropwise by changing the drop
rate in two stages.
<30> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to <29>, wherein the two stages include a
stage corresponding to a first half period of the drop time and a
stage corresponding to a second half period of the drop time,
and
the drop rate during the second half period (the second half
period) of the drop time is preferably 0.2 times or more, more
preferably 0.3 times or more, and further preferably 0.4 times or
more the drop rate during the first half period (the first half
period) of the drop time and is also preferably 0.9 times or less,
more preferably 0.8 times or less, and further preferably 0.7 times
or less the drop rate during one half (the first half period) of
the drop time.
<31> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to <29> or <30>, wherein the two
stages include a stage corresponding to a first half period of the
drop time and a stage corresponding to a second half period of the
drop time, and
the compound of formula (I) is added dropwise so that 55% by mass
or more and 85% by mass or less of the whole amount of addition of
the compound of formula (I) is added during one half (the first
half period) of the chop time, and 15% by mass or more and 45% by
mass or less of the whole amount of addition of the compound of
formula (I) is added during the other half of the drop time.
<32> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <31>, wherein
when the step of reacting the compound of formula (I) with the
compound of formula (II) to provide the .alpha.,.beta.-unsaturated
aldehyde of formula (III) is performed by placing a solution in
which the alkali metal hydroxide is dissolved in the alkanol in a
reaction vessel, then placing the compound of formula (II) in the
reaction vessel, and adding the compound of formula (I) dropwise to
the mixture thus obtained, a discharge portion of the compound of
formula (I) is located above the reaction solution or inside the
reaction solution.
<33> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <32>, wherein
when the step of reacting the compound of formula (I) with the
compound of formula (II) to provide the .alpha.,.beta.-unsaturated
aldehyde of formula (III) is performed by placing a solution in
which the alkali metal hydroxide is dissolved in the alkanol in a
reaction vessel, then placing the compound of formula (II) in the
reaction vessel, and adding the compound of formula (I) dropwise to
the mixture thus obtained, stirring is performed for a certain
time, preferably for 10 minutes to 60 minutes, and more preferably
for 20 minutes to 45 minutes after completion of the addition of
the compound of formula (I).
<34> The method for preparing the .alpha.,.beta.-unsaturated
aldehyde according to any one of <1> to <33>, wherein
after performing the step of reacting the compound of formula (I)
with the compound of formula (II) to provide the
.alpha.,.beta.-unsaturated aldehyde of formula (III), an acid
compound (preferably sulfuric acid, nitric acid, phosphoric acid,
formic acid, acetic acid, propionic acid, or a solution thereon is
added to the reaction vessel so that the alkali metal hydroxide is
neutralized to stop the reaction, thereby avoiding the production
of by-products.
EXAMPLES
In the following examples and comparative examples, unless
otherwise specified, the term "%" means "% by mass."
The materials used in the reaction were as follows:
benzaldehyde: manufactured by Wako Pure Chemical industries, Ltd.,
Wake special grade;
octanal: manufactured by Kao Corporation;
methanol: manufactured by Wake Pure Chemical Industries, Ltd., Wako
special grade;
potassium hydroxide: manufactured by Wake Pure Chemical Industries,
Ltd., Wako special grade;
acetic acid: manufactured by Wako Pure Chemical Industries, Ltd.,
Wako special grade;
tetradecane: manufactured by Wako Pure Chemical Industries, Ltd.,
Wako special grade; and
diethyl ether: manufactured by Wako Pure Chemical Industries, Ltd.,
Wako special grade.
The concentration of moisture in each of the materials was
determined by a volumetric titration method using a Karl Fischer
moisture titrator MKV-710 (manufactured by Kyoto Electronics
Manufacturing Co., Ltd.). The titration solvent was KEMAQUA
Dehydrating Solvent KET (manufactured by Kyoto Electronics
Manufacturing Co., Ltd.). The titrant was KEMAQUA Titrant TR-3
(manufactured by Kyoto Electronics Manufacturing Co., Ltd.).
Example 1
Preparation of hexyl cinnamic aldehyde (formula (III-1))
##STR00008##
First, methanol (128.2 g, 4.0 mol, 400 mol % with respect to
octanal, moisture content: 0.04%, amount of moisture: 0.05 g) and
water (2.6 g) were mixed. Then, potassium hydroxide (purity: 85%,
6.6 g, 0.10 mol, 10 mol % with respect to octanal, moisture
content: 15%, amount of moisture: 0.99 g) was dissolved in the
liquid mixture, and a potassium hydroxide-methanol solution (137.1
g) was prepared. A thermometer, a mechanical stirrer, a condenser,
and a nitrogen line were attached to a 500 mL four-necked separable
flask and thus assembled into a reactor.
The potassium hydroxide-methanol solution (137.1 g) and
benzaldehyde (formula (II-1), 180.4 g, 1.70 mol, 170 mol % with
respect to octanal, moisture content; 0.05%, amount of moisture:
0.09 g) were added to the reactor. Subsequently, a 200 mL flask
containing octanal (formula (I-1)) was connected to the reactor via
a dropping pump. The inside of the reactor was replaced with
nitrogen. The reactor was placed in a warm bath at 30.degree. C.,
and stirring (500 rpm) of the contents in the reactor was started.
After 5 minutes passed, dropping of octanal into the reactor was
started. The octanal was drooped into the reactor at 25.6 g/hour
for 3 hours, and then at 17.1 g/hour for 3 hours. Thus, it took a
total of 6 hours to drop the octanal (128.2 g, 1.0 mol, amount of
moisture: 0 g) into the reactor. The total amount of water
contained in the materials that were used in the reaction was 3.73
g (20.7 mol % with respect to octanal). The stirring of the
contents in the reactor was continued at 30.degree. C. for 0.5
hours after the dropping of the octanal was completed. Then, acetic
acid (5.0 g, 0.08 mol, 8.3 mol % with respect to octanal) was added
to the reactor to stop the reaction in the reactor, so that the
reaction was finished.
Using gas chromatography (GC), a quantitative analysis of the
reaction product was performed by an internal standard method to
determine the composition for each component of the reaction
product. The results of the reaction were calculated by the
following formulas based on the composition of the reaction product
thus obtained. The internal standard substance was tetradecane, and
the solvent was diethyl ether. Table 1 shows the calculated dimer
formation rate and selectivity of hexyl cinnamic aldehyde (with
respect to benzaldehyde).
Specifically, 0.3 mL of the reaction solution was sampled, put in a
screw bottle, and precisely weighed. Then, 0.1 g of tetradecane was
added to the reaction solution and precisely weighed. Moreover, 1
mL of a phosphate buffer and 3 mL of ether were added to the
reaction solution and shaken. This liquid was allowed to stand
still so that oil was separated from water. The upper layer was
analyzed by GC.
The GC analysis used both DB-1 column (GC column, 100%
dimethylpolysiloxane, manufactured by Agilent Technologies Japan,
Ltd.) and DB-WAX column (GC column, polyethylene glycol,
manufactured by Agilent Technologies Japan, Ltd.).
[Dimer Formation Rate]
A dimer formation rate, which is a measure of the dimerization of
aldehydes, was calculated by the following formula. A smaller value
indicates better performance. Dimer formation rate [%]=[GC area of
dimer in product]/[GC area % of hexyl cinnamic aldehyde in
product]
[Selectivity of Hexyl Cinnamic Aldehyde (with Respect to
Benzaldehyde)]
A selectivity of hexyl cinnamic aldehyde (with respect to
benzaldehyde), which is a measure of the disproportionation of
aldehydes, was calculated by the following formula. A larger value
indicates better performance.
Selectivity of hexyl cinnamic aldehyde (with respect to
benzaldehyde) [%]=([mass of hexyl cinnamic aldehyde in
product]/[molecular weight of hexyl cinnamic aldehyde])/{([mass of
benzaldehyde introduced]-[mass of benzaldehyde in
product])/[molecular weight of benzaldehyde]}.times.100
Example 2
Example 2 was performed in the same manner as Example 1 except that
the amount of potassium hydroxide was changed from 10 mol % to 12
mol % with respect to octanal, and the total amount of water
contained in the materials that were used in the reaction was
changed from 20.7 mol % to 21.4 mol % with respect to octanal.
Table 1 shows the results of the evaluation of the product thus
obtained.
Example 3
Example 3 was performed in the same manner as Example 1 except that
the amount of potassium hydroxide was changed from 10 mol % to 8
mol % with respect to octanal, and the total amount of water
contained in the materials that were used in the reaction was
changed from 20.7 mol % to 19.2 mol % with respect to octanal.
Table 1 shows the results of the evaluation of the product thus
obtained.
Comparative Examples 1 to 3
Comparative Examples 1 to 3 were pet formed in the same manner as
Example 1 except that the amount of potassium hydroxide and the
total amount of water contained in the materials that were used in
the reaction were changed as shown in Table 1. Table 1 shows the
results of the evaluation of the products thus obtained. In Table
1, the amount of potassium hydroxide (KOH equivalent) represents a
mole percent (mol %) with respect to octanal. In Table 1, the total
amount of water contained in the materials that were used in the
reaction, which was the sum of the amount of moisture contained in
methanol, potassium hydroxide, and benzaldehyde and the amount of
moisture added separately to the reactor, represents a mole percent
(mol %) with respect to octanal.
Table 1 shows the reaction conditions and the results in Examples 1
to 3 and Comparative Examples 1 to 3.
TABLE-US-00001 TABLE 1 Total amount of water Selectivity of hexyl
cinnamic Dimer KOH contained in materials aldehyde (with respect to
formation equivalent used in reaction benzaldehyde) rate (mol %)
(mol %) (%) (%) Comp. Ex. 1 6 18.6 93.7 1.30 Ex. 3 8 19.2 92.5 1.01
Ex. 1 10 20.7 93.8 0.89 Ex. 2 12 21.4 92.3 1.00 Comp. Ex. 2 14 22.8
88.0 0.74 Comp. Ex. 3 17 24.9 87.9 0.67
Example 4
Example 4 was performed in the same manner as Example 1 except that
the total amount of water contained in the materials that were used
in the reaction was changed from 20.7 mol % to 13.5 mol % with
respect to octanal. Table 2 shows the results of the evaluation of
the product thus obtained.
Example 5
Example 5 was performed in the same manner as Example 1 except that
the 1.5 total amount of water contained in the materials that were
used in the reaction was changed from 20.7 mol % to 27.7 mol % with
respect to octanal. Table 2 shows the results of the evaluation of
the product thus obtained.
Example 6
Example 6 was performed in the same manner as Example 1 except that
the total amount of water contained in the materials that were used
in the reaction was changed from 20.7 mol % to 42.0 mol % with
respect to octanal. Table 2 shows the results of the evaluation of
the product thus obtained.
Comparative Examples 4 to 9
Comparative Examples 4 to 9 were performed in the same manner as
Example 1 except that the amount of potassium hydroxide and the
total amount of water contained in the materials that were used in
the reaction were changed as shown in Table 2. Table 2 shows the
results of the evaluation of the products thus obtained. In Table
2, the amount of potassium hydroxide (KOH equivalent) represents a
mole percent (mol %) with respect to octanal. In Table 2, the total
amount of water contained in the materials that were used in the
reaction, which was the sum of the amount of moisture contained in
methanol and potassium hydroxide and the amount of moisture added
separately to the reactor, represents a mole percent (mol %) with
respect to octanal.
TABLE-US-00002 TABLE 2 Total amount of water Selectivity of hexyl
cinnamic Dimer KOH contained in materials aldehyde (with respect to
formation equivalent used in reaction benzaldehyde) rate (mol %)
(mol %) (%) (%) Comp. Ex. 4 10 6.4 88.4 0.83 Comp. Ex. 5 10 8.5
88.1 0.86 Comp. Ex. 6 10 9.3 87.9 0.85 Ex. 4 10 13.5 92.4 0.79 Ex.
5 10 27.7 93.4 0.91 Ex. 6 10 42.0 93.1 1.01 Comp. Ex. 7 10 77.6
89.4 1.15 Comp. Ex. 8 10 131.1 92.3 1.56 Comp. Ex. 9 10 184.6 94.0
2.11
The results in Tables 1 and 2 confirmed that when the compound of
formula (I) was reacted with the compound of formula (II) to
provide the .alpha.,.beta.-unsaturated aldehyde of formula the
selectivity of the .alpha.,.beta.-unsaturated aldehyde (with
respect to the compound of formula (II)) was high and the dimer
formation rate was low under the condition that the total amount of
water contained in the materials that were used in the reaction was
10 mol % to 50 mol % with respect to the compound of formula (I),
the amount of the alkali metal hydroxide was 8 mol % to 12 mol %
with respect to the compound of formula (I), and alkanol having 1
to 4 carbon atoms was used.
INDUSTRIAL APPLICABILITY
The preparation method of the present invention can prepare a
target aldehyde with high selectivity and also can suppress the
production of by-products. Therefore, the
.alpha.,.beta.-unsaturated aldehyde can be prepared with high
efficiency and high purity. The preparation method of the present
invention can be suitably used as a method for preparing an
aldehyde that is useful as a fragrance material.
* * * * *